The study revealed the important role of circadian clock genes in the flight and reproductive behavior of Oriental armyworms

Recently, the innovation team of food crop pest monitoring and control of the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences published a paper entitled "The clock gene, period, influences migratory flight and reproduction of the oriental armyworm, Mythimna separata (Walker)" in Insect Science.
It was revealed that circadian clock genes play an important role
in the flight and reproductive behavior of Oriental armyworms.

Mythimna separata (Walker) is a major migratory pest on the three major staple crops of corn, wheat and rice in China, known as "god worm" since ancient times, and was listed in the national list of first-class crop diseases and pests in 2020, posing a major threat
to national food security and biosecurity.
Every year, the hazard of seasonal north-south round-trip migration in the vast area of China is presented, and long-distance migration and high spawning are important factors
in its outbreak.
The migration and spawning behavior of adult armyworms mainly occurs at night, with obvious seasonal and circadian rhythms, but the molecular regulation mechanism of armyworm flight and reproductive behavior rhythms is still not clear
.

Circadian clock genes regulate the behavior, physiology and metabolic rhythm of insects at all levels, which are essential factors for maintaining individual life activities and key genes affecting population dynamics
.
In this study, the circadian clock gene period (MSPER)
encoding 1192 amino acids was first identified in the migratory oriental armyworm.
Quantitative PCR showed that Msper expression was spatiotemporal specific, mainly expressed in adult antennae, and produced significant rhythmic changes
with light and dark phases.

The insect autonomous flight activity monitoring device was used to observe that the injection of efficient siRNA could effectively interfere with the expression of armyworm Msper, and the nocturnal flight activity of migratory adults after Msper interference was significantly reduced, and did not show the normal peak of nocturnal flight activity, and the adult could not complete the normal mating and egg-laying behavior, but when the expression level of Msper was restored, the mating ability and egg production of adults could return to normal levels
.

This study is the first to explore the regulatory role
of circadian clock genes in the flight and reproductive behavior of Oriental armyworms.
Given the important role of MSPER in regulating armyworm flight ability and reproduction, it is implied that this gene can be used as an effective molecular target in the comprehensive management of Oriental armyworm
.

Ji Jiayue and Zhang Lei, graduate students of the Institute of Plant Protection, Chinese Academy of Agricultural Sciences, and Liu Yueqiu, associate professor of Beijing Agricultural College, are the co-first authors
of this paper.
Jiang Xingfu, a researcher at the Institute of Plant Protection, Chinese Academy of Agricultural Sciences, is the corresponding author
.
This research was supported by the National Natural Science Foundation of China (32072420, 31672019), the National Green Manure Industry Technology System (CARS-22), the National Key Research and Development Program of China (2017YFD0201802, 2017YFD0201701) and the Beijing Natural Science Foundation (6172030
).